Method of and apparatus for leading off and cooling of converter gases



G OFF AND TUS FOR LEADIN ONVERTER GASES 4, 1964 H. HOFF METHOD OF ANDAPPARA COOLING OF C Filed July 12, 1960 United States Patent 3,143,411lvtETl-IOD OF AND APPARATUS FOR LEADING OFF AND CQOLING OF CONVERTERGASES Hans Hofi, Essea-Bredeney, Germany, assignor to BeteiligungsundPatentverwaltungsgeseilschaft mit beschrankter Haftung, Essen, Germany,a corporation of Germany Filed July 12, 196i Ser. No. 42,319 Claimspriority, application Germany July 18, 1959 7 Claims. (Cl. 75-48) Thepresent invention relates to a method of and apparatus for leading otfand cooling of converter gases.

It is already known to feed converter gases to a dust removing device,particularly those gases created during the fining of pig-iron withoxygen, and hereby, to avoid the admixture and the burning of thecombustible ingredients with air, in order to maintain, as low aspossible, the quantity of gases the dust of which has to be removed.

In order to achieve this end, the gases led off the converter are caughtby means of a cap mounted on the mouth formation of the converter andthen fed to the dust removing device after cooling with spray water.This operation has the drawback that cooling by means of the spray Waterbecomes eifective only after expiration of a predetermined tirne period,since at first the water drops must be transformed into steam, so thatonly after a greater or shorter flow of the gases, depending upon thesize of the drops, the full cooling etfect is obtained. Furthermore, thecooling achieved, nearly exclusively, by a water injection requiresgreat quantities of water in view of the high starting temperature ofthe gases led oil the converter and brings about, therefore, a highhumidity content of the gases and a correspondingly high dew-point,whereby the heating value of the gases is reduced and its quantities areundesirably increased.

It is, therefore, one object of the present invention to provide amethod of leading off and cooling of converter gases, wherein thesedrawbacks are avoided by leading off and cooling of the gases from theconverter with avoidance of air feed by using of a cap mounted on themouth formation of the converter in such a manner that cooling gases arefed into the conduit in which the gases are removed. Preferably wastegases from blast furnaces are used for the cooling, which Waste gasesare suitably applied in a pro-purified state and at the conventionaltemperature of about 70 C. after the pre-purification. In addition,nitrogen could also be considered, which nitrogen is obtained during theoxygen production.

It is another object of the present invention to provide a method ofleading off and cooling of converter gases, wherein by the admixture ofthe gases led off the converter with more or less purified waste gases,an immediately effective cooling is brought about. Simultaneously, orthereafter, cooling with spray water can also be provided, whereby,however, the water quantity and thereby also the humidity content of thegases is not to be measured greater than required for the dust removingprocess, as the circumstances require. The heat transfer of the gases tothe conduit by spraying is further increased by the waste gases and,therefore, the indirect cooling by means of the conduit wall, isincreased.

It is yet another object of the present invention to provide a method ofand apparatus for leading OE and cooling of converter gases, wherein thedew-point of the gases to be removed may be kept at a lower point by theapplication of blast furnace gases for the cooling than in the case ofexclusive direct cooling with Water. For

3,143,411 Ce l 'ate nted Aug. 4, 1964 instance, the dew-point of pureCO-gas is, in the case of a direct cooling by means of evaporation ofwater with a temperature of the gases of 1700 C., at about 83 C., andwith additional indirect cooling of from 1700 C. to 1,000 C., at aboutC. On the other hand, the dew-point of the gas mixture amounts to about75 C. without indirect cooling by a mixture ratio of two parts of blastfurnace gas and one part of converter gas, or, in case of a mixtureratio of ten parts of waste gas and one part of converter gas, about 50C. In case of additional indirect cooling from 1700 C. to 1000" C., thecorresponding dew-point values lie at about 67 C. and 42 C. In similarmanner, the specific humidity of the gas mixture is naturally loweredand reaches in the mixture ratio of 10:1 about the value which the blastfurnace gases had at the time of their entrance. Upon additionalindirect cooling from 1700 C. to 1000 C., the specific humidity of thegas mixture is only 0.7 times of the specific humidity of the wastegases, in spite of the direct cooling. A low humidity of the gases ledoff brings about a higher heating value, as is well known. A lowerdew-point permits lower operation temperatures of the dust removingdevice, for instance of the textile material filter and the dryelectro-filter and thus constitutes an advantage.

It is a further object of the present invention to provide a method ofand apparatus for leading off and cooling of converter gases, whereinthe feeding of waste gases into the conduit for the gases led off is notin terrupted during the stoppage of the blowing. The conduit for thegases to be led off is closed up against the outer atmosphere, in orderto avoid detonations and explosions. The continuous feeding of wastegases has the advantage, that a continuously flowing energy carrier isavailable to the operator without requiring an intermediate storagethereof. Furthermore, it is also avoided that always at the start of theblowing, the gas to be removed enters an air filled conduit. Theproposed cleaning of the entire conduit system with nitro gen, in orderto avoid explosions, is then superfluous.

Since pre-purified blast furnace gas can be used in the processaccording to the present invention, the device for removing fine dustfrom the waste gas is correspondingly discharged and can have a smallermeasurement. The dust removing device for the converter gases to be ledoff is better utilized than in the case of an interrupted operation. Thecoarser dust of the waste gases can be considered further as catch dustfor the fine dust of the gases led off the converter.

With these and other objects in View, which will become apparent in thefollowing detailed description, the present invention will be clearlyunderstood in connection with the accompanying drawing, in which theonly figure is an elevation, partly in section, of an apparatus adaptedfor leading off the gases obtained by blowing of oxygen on a pig-ironmelt.

Referring now to the drawing, the apparatus comprises a converter 1 andthe cap 2 is mounted on the converter 1, in order to catch the gases tobe led off, in order to avoid the entrance of air and the burning of thegases with air, which gases consist to about of CO. The cap 2 isWater-cooled. The cooling water enters at the branch 3 and leaves at thebranch 4. The cap 2 has an opening 5 through which an oxygen feeder 6,shown in point dotted lines, is sealingly inserted. An opening (notshown) may also be provided on the cap 2 for the feeding of addedmaterial, as well as another opening (not shown) from which a smallquantity of gas may escape for the purpose of observation.

A feeding housing 8 for the waste gases is provided between the cap 2and the conduit 7 for the gases to be led ed, in which housing 8 thewaste gases enter into the gas conduit through an annular slot 9, thewaste gases being fed through the conduit 10. The conduit 7 for thegases to be led off is surrounded with a cooling water jacket 11 andequipped with connecting branches 12 for the water spray nozzles. Aclosing member formed as a Water-cooled throttle damper 13 or as watervalve or slide, is provided between the cap 2 and the gas conduit 7.

The gas conduit 7 is connected to the conduit 15, leading to the dustremoving device, on the end opposlte to that of the feeding housing 8for the waste gases with a packing 14, which permits a swinging of thegas conduit 7. By the hydraulic or electric lifting device 16, the gasconduit 7 can be moved upwardly and downwardly, respectively, includingthe cap 2 and the feeding housing 8 for the waste gases.

The working of this apparatus takes place in the fol-' lowing manner:

Upon filling the pig-iron into the converter 1, the cap 2 is mounted onthe converter by operation of the lifting device 16, whereby the cap 2is closed up from the gas conduit 7 by the closed damper 13. Uponinsertion of the blow feeder 6, oxygen is blown into the pig-iron bath,whereby the cap 2 is filled with the, gases to be led off and the gasoverflow can escape through a slot between the converter 1 and the cap2. Upon opening of the damper 13, the gases to be led off flow into theconduit 7 whereby they are cooled by means of the waste gases enteringthrough the slots 9. For further cooling, spray water is fed through thenozzles 12. The cooled gas mixture is then fed to the dust removingdevice through the conduit 15. Shortly prior to the termination of theblowing, the damper 13 is closed again, and upon termination of theblowing, the conduit 7 swings up with the cap 2 and the converter istipped over. The waste gas continues to flow during that time into theconduit 7 and prevents by the overpressure the entrance of air into theconduit, possibly by leak'iness of the closing damper 13.

While I have disclosed one embodiment of the present invention, it is tobe understood that this embodiment is given by example only and not in alimiting sense, the scope of the present invention being determined bythe objects and the claims.

I claim:

1. A method of leading off and cooling of converter gases by means of acap mounted on the mouth of a converter and leading into a conduit,comprising the steps of feeding a stream of converter gases from aconverter through a cap,

feeding selectively said stream of converter gases from said cap into aconduit and throttling said stream of converter gases prior to theirentrance into said conduit, respectively, and

feeding cooling gases continuously into said conduit at a pointdownstream from said throttling point and selectively joining saidstream of converter gases in said conduit during nonthrottling of saidstream of converter gases and feeding solely said cooling gases intosaid conduit during throttling of said stream of converter gases at apoint upstream of the point of entrance of said cooling gases.

2. The method, as set forth in claim 1, wherein said cooling gases areblast furnace gases and said feeding of cooling gases is performedduring the blowing and nonblowing period.

3. An apparatus for leading off and cooling of gases from converters,comprising a converter having a mouth formation, a cap mounted on saidmouth formation of said converter, a conduit for leading off gases fromsaid converter connected with the free end of said cap, a closing memberdisposed between said cap and said conduit, a housing for feedingcooling gases into said conduit and disposed between said closing memberand said conduit, and another conduit terminating in said feedinghousing and feeding said cooling gases into said housing during theclosed as well as open position of said closing member.

4. The apparatus, as set forth in claim 3, wherein said feeding housingdefines an annular entrance slot at the point of connection with saidfirst-mentioned conduit.

5. The apparatus, as set forth in claim 4, wherein said annular entranceslot is directed towards said closing member.

6. The apparatus, as set forth in claim 3, wherein said first-mentionedconduit has a plurality of connecting branches spaced apart from eachother along the longitudinal axis of said first-mentioned conduit.

7. The apparatus, as set forth in claim 3, which includes a liftingdevice raising off said cap from and setting down the latter on,respectively, said converter, and means for swinging saidfirst-mentioned conduit together with said feeding housing for saidcooling gases out of its operative position, in order to disconnect saidfeeding housing from the free end of said cap.

References Cited in the file of this patent UNITED STATES PATENTS 86,247Phillips Jan. 26, 1869 233,505 Hall e Oct. 19, 1880 698,610 Wills Apr.29, 1902 1,417,588 Amburgh 1 May 30, 1922 1,866,824 Sheridan July 12,1932 2,729,301 Ekstrom Jan. 5, 1956 2,803,450 McFeaters Aug. 20, 19572,831,467 Guczky Apr. 22, 1958 2,831,762 Kemmetmuller Apr. 22, 19582,855,292 Vogt Oct. 7, 1958 2,862,701 McFeaters Dec. 2, 1958 FOREIGNPATENTS 772,632 Great Britain Apr. 17, 1957 1,020,355 Germany Dec. 5,1957 972,340 Germany July 9, 1959

1. A METHOD OF LEADING OFF AND COOLING OF CONVERTER GASES BY MEANS OF ACAP MOUNTED ON THE MOUTH OF A CONVERTER AND LEADING INTO A CONDUIT,COMPRISING THE STEP OF FEEDING A STREAM OF CONVERTER GASES FROM ACONVERTER THROUGH A CAP, FEEDING SELECTIVELY SAID STREAM OF CONVERTERGASES FROM SAID CAP INTO A CONDUIT AND THROTTLING SAID STREAM OFCONVERTER GASES PRIOR TO THEIR ENTRANCE INTO SAID CONDUIT, RESPECTIVELY,AND FEEDING COOLING GASES CONTINUOUSLY INTO SAID CONDUIT AT A POINTDOWNSTREAM FROM SAID THROTTLING POINT AND SELECTIVELY JOINING SAIDSTREAM OF CONVERTER GASES IN SAID CONDUIT DURING NONTHROTTLING OF SAIDSTREAM OF CONVERTER GASES AND FEEDING SOLELY SAID COOLING GASES INTOSAID CONDUIT DURING THROTTLING OF SAID STREAM OF CONVERTER GASES AT APOINT UPSTREAM OF THE POINT OF ENTRANCE OF SAID COOLING GASES.